In the Academy-Verse reality has a tri-fold structure. The scientific research on this is a relatively young discipline, only really coming into recognition with the Greater Emergence. The scientific discipline is known as Planar Studies, the subject itself will often be referred to as the Trinitary Nature or Structure of Reality, or simply the Trinity for short - not to be confused with the Christian Trinity. The three distinctions made in Planar Studies are between the Physical, the Spiritual and the Mental.
The physical plane is the one most people are intimately familiar with. It contains what we casually refer to as the Universe, everything contained within the physical plane consists of either some kind of matter or some form of energy. This is the plane that is best understood by science, all laws of physics, chemistry, biology and so forth apply. Entities who are primarily physical in nature are referred to as Organisms. Many species' of organisms, including humans, have connections to both the mental and the spiritual planes. An organism has better chances of possessing these connections, the higher evolved their brains are, but there have been instances shown of microbes or similarly non-sentient Organisms having links to the other planes. As natural sciences have already mapped out the physical plane rather well no distinctive discipline for the study of the physical plane has been established.
Often times also referred to as the magical or mystical plane the spiritual plane is the second most well understood of the three planes. It is the source of the magical powers and mystical abilities of that inspired the legends of old, and is most directly tied into an entities emotions. Everything within the spiritual plane consists of so-called Thaumine. Thaumine exhibits behaviours typical of both matter and energy as we see them on the physical plane, but also a number of unique properties. For example so far it appears like there is no eqivalent to Conservation of Energy regarding Thaumine. The spiritual plane has no geography as we would traditionally understand it, instead the are pockets of spacetime referred to as Realms. Realms are interconnected with dimensional apertures called Portals. A realm may look and act much like the physical plane, or it may be extremely alien to the human perception, to the point where some of the most exotic realms defy perception and recording and cause catatonic coma when experienced. Portals may also connect to the mental plane, or specific spacetime coordinates on the physical plane. Entities who are predominately spiritual have serveral different labels applied to them, ghosts, apparitions, manifestations and many more, often borrowed from ancient mythology. The science of the spirtual plane, Thaumatology, refers to them as Spirits. Spirits thend to be highly emotional, with little capacity for analytical thought, which leads many to classify them as non-sapient. Thaumabiologists, however, have determined that many species' of Spirits display all the criteria of sapience, such as a sense of individuality, being able to contemplate and refer to past, future and non-real events and the capability to solve problems. While a great deal of Spirits have ties to the physical world it is very rare to find one that are tapped into the mental plane.
The most recently discovered and recognized among the three planes of reality, the mental or psychic plane is the least well understood. The running theory is that it emerged with the onset of sapience and is the culmination of all thoughts and ideas of sapient and semi-sapient beings, which includes many of the more intelligent mammals and even some reptiles. In the study of the mental plane, Psychography, it has been determined that the mental plane is one continuous expanse in all imaginable directions, with seemingly no end. There are certain partitions within this expanse, referred to as Folds. Each fold is always connected to at least one individual mind, which caused the fold to appear, however not every sapient mind has a fold and not all of those who have a fold are aware of it. Entities who are of a mainly mental nature are known as Constructs or Creations, which is derived from the running theory that without the minds of sapient beings the mental plane would not exist either. Not much is known about the composition or substance of the mental plane, and since Constructs are few and far between, and them communicating with others is even less common, not much is known about them either.
THE TRINITY AND META-HUMANS Edit
While the trinitary nature of reality usually doesn't affect standard humans much it is of greater importance to Meta-Humans. Their extraordinaire abilities are often predominately or even exclusively rooted in one of the planes. While it can be shown that certain power types occur more frequently from certain Source Planes, there seems to be no restrictions; any power may come from any source. This is best explained when one segments a power into effet and vector: The effect is the end result, what actually happens to the world when the power is used. This might be the conjuration of a fireball, running at super-sonic speeds or telepathic control over animals. The vetor, on the other hand, references the way in which the effect is achieved. A speeder might have extremely dense muscles in his legs and hip (physical source), he might be born with innate knowledge of a spell that gives him higher speed (spiritual source) or he might have the ability to propel himself forward telekinetically (psychic source). The source plane is of no importance for usage and effect of powers, but it becomes very relevant as soon as one ventures to dampen or neutralize powers, or perhaps strengthen them.